1. Field of the Invention
The present invention relates to swimming aids, and, more particularly, is directed towards a fin which extends outwardly away from the feet of the swimmer at an angle to the swimmer's feet, and to an improved swimming garment incorporating an improved swim fin.
2. Description of the Prior Art
A wide variety of swimming aids for use on a swimmer's feet are known. Such swimming aids may comprise a single fin which receives both feet of the swimmer or a pair of fins, in which each fin receives one foot of the swimmer. A swimming aid which receives both feet of the swimmer is exemplified by U.S. Pat. Nos. 3,934,290 and 4,044,174 to LeVasseur, and is characterized by the way it substantially aligns with the plane of the swimmer's body when the feet are extended for swimming. Moreover, the substantially rectangular cross-section of the LeVasseur fin is a disadvantage because it does not enhance the swimmer's strength or speed. An integral swimming suit and swim fin is disclosed in the LeVasseur U.S. Pat. No. 4,055,174; a snorkel is built into the suit as well.
There are numerous designs for swimming aids which are used in pairs. Many, as exemplified by U.S. Pat. No. 3,302,223 to Ciccotelli, U.S. Pat. No. 3,315,286 to Brion, and U.S. Pat. No. 3,665,535 to Picken, are characterized by blades which extend from the toe of a shoe, and which reciprocate as the swimmer kicks his legs. Such a design has numerous disadvantages. Because the user kicks his legs separately, the blades which extend from each foot are likely to hit each other in passing. The pivoting of the blade does not allow the swimmer to control the angle of attack during the upstroke and the downstroke. Therefore, the design does not appreciably increase the swimmer's speed and strength.
Another swimming aid which receives both feet of the swimmer is exemplified by U.S. Pat. No. 3,987,509 to Patterman. In this design, the feet extend in opposite directions, toe to heel, a position at once uncomfortable and difficult to maintain.
Some swimming aids are characterized by a blade which is rigid in use, but fixed at an angle to the soles of the swimmer's feet. The angle results in the blade being aligned with the swimmer's lower leg. As a result, the swimmer's upstroke is extremely inefficient. Such a design is exemplified by U.S. Pat. No. 4,025,977 to Cronin.
It is known that a blade in the shape of a hydrofoil provides greater lift than a blade which is flat. Swimming aids which incorporate this concept are exemplified by U.S. Pat. No. 3,073,932 to Ciccotelli, U.S. Pat. No. 3,665,535 to Picken and U.S. Pat. No. 3,987,509 to Patterman. Ciccotelli does not appreciate the significance of the hydrofoil shape, and places it on a flexible beam past the end of the swimmer's toe. The flexibility of the beam prohibits the swimmer from controlling the angle of attack, and the size and location of the hydrofoil further detract from its efficiency. The hydrofoil used by Picken also is subject to reciprocating motion, and is beyond the end of the swimmer's toe. Thus, although Picken recognizes the advantage of using a hydrofoil, its use is not optimized. Patterman places the sharp edge of the hydrofoil in the direction of the swimmer's head. In order for the hydrofoil to create the desired lift, the sharp edge of the hydrofoil must point away from the swimmer's head. Patterman therefore not only does not appreciate the hydrofoil concept, but also makes improper use of it.
Other United States patents which relate generally to swimming aids include U.S. Pat. Nos. Des. 132,377; U.S. Pat. Nos. 2,950,487; 3,084,355; and 3,165,764. However, none of the structures described in these patents solve the problems noted above.
Italian Pat. No. 676,938 to Alinari shows a swim fin in which an hydrofoil shape is provided traversely to the direction of the motion of the swimmer. The hydrofoil is of an aspect ratio of approximately 3 to 1, and is spaced from the toe of the swimmer by a beam member. While use of an hydrofoil in the swim fin is very desirable, as will be discussed in detail below in connection with Applicant's invention, spacing the hydrofoil away from the toe of the swimmer is very undesirable as it obliges the user to exert very high torque to move the hydrofoil through the water. Moreover, the construction shown in the Alinari patent is not optimal with respect to the shape of the hydrofoil and its relationship to the direction of movement of the swimmer through the water, as will also be explained in detail below.
Ganev U.S. Pat. No. 3,521,312 shows a combined swim shoe and fin, in which the fin is removably attached to the shoe. The fin is of low aspect ratio and does not include an effective hydrofoil shape.